Some people keep the thermostat in their homes set at a constant level, day in and day out, thinking that maintaining a consistent temperature saves energy. The reality is that most homes take only 15 to 30 minutes to heat up or cool down, so running the air conditioning or heating system at the same temperature 24 hours a day can waste a lot of energy — and costs a lot of money. It’s a little like keeping a kettle running on the stove 24-hours a day in case you might like a hot drink sometime during the day! Homeowners can of course control heating and cooling by manually changing the thermostat as they come and go — or before they head off to sleep. But even the most conscientious person can forget at times.

To simplify your life and save energy, consider installing a programmable thermostat. These devices monitor and control heating and cooling systems automatically, based on your schedule. For example, they can be programmed to turn down the heat at night a half hour before you and your family head off to bed, say to 55°F to 60°F, and then turn it back up to 68°F to 70°F a half hour before you awaken. You can also program your thermostat to turn the heat down again as you and your family head off to work and school, then turn it up again a half hour before you arrive home.

Programmable thermostats can also be used to control air conditioning. You can even program in a separate weekend setting. Programmable thermostats typically come with a manual override, so you can set the temperature differently on days when your routine changes.

Home improvement centers and hardware stores carry a variety of programmable thermostats ranging in price from about $50 to over $250. Features vary, so shop carefully, and for best performance, select an Energy Star®-rated thermostat.

Programmable thermostats are easy to install and can reduce your energy bills by 10% or more per year, if properly programmed. They’re also good for the environment — less energy use means less environmental pollution from power plants, especially greenhouse gas emissions.

Convenience is a great feature of these thermostats, since you’ll no longer need to adjust the temperature when going to bed or leaving the house. And lastly, your heating and air conditioning equipment won’t run as often, meaning less noise and reduced wear and tear — which results in lower maintenance, repair, and replacement costs.

This article was excerpted from Green Home Improvement, By Daniel D. Chiras, PhD, available through RSMeans.